U.S. patent application number 14/386113 was filed with the patent office on 2015-04-09 for direct drive for a rotation machine, particularly for a container treatment machine.
This patent application is currently assigned to Schaeffler Technologies GmbH & Co. KG. The applicant listed for this patent is Schaeffler Technologies GmbH & Co. KG. Invention is credited to Thomas Dittenhofer, Gunter Schmid, Ralf Schuler.
Application Number | 20150097454 14/386113 |
Document ID | / |
Family ID | 47664249 |
Filed Date | 2015-04-09 |
United States Patent
Application |
20150097454 |
Kind Code |
A1 |
Schmid; Gunter ; et
al. |
April 9, 2015 |
DIRECT DRIVE FOR A ROTATION MACHINE, PARTICULARLY FOR A CONTAINER
TREATMENT MACHINE
Abstract
A direct drive for a rotation machine, particularly for a
container treatment machine, this drive including a fixed machine
part (1) and a machine part (2) rotating around a vertical machine
axis, wherein the rotating machine part (2) is rotationally
connected to the fixed machine part (1) by a roller bearing (3)
arranged between the two machine parts (1, 2) and having an outer
bearing ring (4), an inner bearing ring (5) and a plurality of
rolling elements rolling between said bearing rings (4, 5), and can
be driven by a torque motor (7). On the rotating machine part (1),
a plurality of magnets (8) is provided, surrounding the rotating
machine part, while on the fixed machine part (1), a stator (12)
formed of a plurality of electric coils (9, 10, 11) is arranged,
such that the rotating machine part (2) can be set in a defined
rotational motion through an electromagnetic field generated when
the stator (12) is energized in cooperation with the magnets (8).
The stator (12) on the fixed machine part (1) is formed as a full
ring of 360.degree. covering, without gaps, all magnets (8) on the
rotating machine part (2), this full ring being composed of a
number of stator ring segments (13.1, 13.2, 13.3, 13.4, 13.5)
adjacent to one another and connected to one another by an
electrical series connection and also composed of a number of stop
elements (14.1, 14.2, 14.3, 14.4, 14.5) arranged between the stator
ring segments (13.1, 13.2, 13.3, 13.4, 13.5) for fixing the stator
ring segments (13.1, 13.2, 13.3, 13.4, 13.5) in a circumferential
and radial direction.
Inventors: |
Schmid; Gunter; (Nurnberg,
DE) ; Dittenhofer; Thomas; (Humprechtshausen, DE)
; Schuler; Ralf; (Wichtshausen, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schaeffler Technologies GmbH & Co. KG |
Herzogenaurach |
|
DE |
|
|
Assignee: |
Schaeffler Technologies GmbH &
Co. KG
Herzogenaurach
DE
|
Family ID: |
47664249 |
Appl. No.: |
14/386113 |
Filed: |
January 23, 2013 |
PCT Filed: |
January 23, 2013 |
PCT NO: |
PCT/EP2013/051205 |
371 Date: |
September 18, 2014 |
Current U.S.
Class: |
310/71 ; 310/68B;
310/68D; 310/75R |
Current CPC
Class: |
H02K 11/21 20160101;
H02K 1/185 20130101; H02K 26/00 20130101; B67C 3/22 20130101; H02K
7/08 20130101; H02K 5/10 20130101; H02K 3/522 20130101 |
Class at
Publication: |
310/71 ;
310/75.R; 310/68.B; 310/68.D |
International
Class: |
H02K 7/08 20060101
H02K007/08; H02K 5/10 20060101 H02K005/10; H02K 1/18 20060101
H02K001/18; H02K 11/00 20060101 H02K011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 23, 2012 |
DE |
102012204721.2 |
Claims
1. A direct drive for a rotation machine, comprising a fixed
machine part and a machine part which rotates about a vertical
machine axis and is rotationally connected to the fixed machine
part by a roller bearing arranged between the two machine parts
that includes an outer bearing ring, an inner bearing ring and a
plurality of rolling elements rolling between said bearing rings,
and which is driven by a torque motor, a plurality of peripherally
continuously arranged magnets on the rotating machine parts and a
stator made up of a plurality of electric coils arranged on the
fixed machine part, the rotating machine part being rotatable by an
electromagnetic field generated by energizing the stator, in
interaction with the magnets, to be set into a defined rotational
motion, the stator on the fixed machine part is configured as a
full ring of 360.degree., and covers all the magnets on the
rotating machine part without any gap while being made up of a
plurality of adjoining stator ring segments that are connected to
one another through an electrical series connection, and a
plurality of stop elements disposed between the stator ring
segments that fix the stator ring segments in circumferential and
in radial directions.
2. The direct drive according to claim 1, wherein each of the
individual stator ring segments comprises a ferrous metal yoke and
a plurality of toothed metal sheets stacked on one another on an
upper and a lower side of the yoke with copper coils wound around
teeth of the sheets for forming individual electric coils.
3. The direct drive according to claim 2, wherein the individual
coils of the stator ring segments are connected electrically in
series through a star-delta connection with three electrically
offset phases of 120.degree. and are controllable through a single
servo controller with a voltage intermediate-circuit converter.
4. The direct drive according to claim 3, wherein all adjoining
ones of the stator ring segments are connected via a respective
connecting cable to one another with a plug connector and only one
first and one last one of the stator ring segments comprises, in
place of a connecting cable, a servo controller connection or a
star-delta element.
5. The direct drive according to claim 2, wherein the stop elements
arranged between the stator ring segments have a shape of circular
ring segments that are in abutting contact with the yoke and have a
lengthened shape and with radial side surfaces of the stator ring
segments.
6. The direct drive according to claim 5, wherein one of the stop
elements acts as a holder for a scanning sensor that, with an
incremental or absolute, magnetic or inductive angular pitch
graduation, forms on the rotating machine part, a measuring system
for determining a position of the rotating machine part.
7. The direct drive according to claim 6, wherein the magnets of
the torque motor and the angular pitch graduation of the measuring
system are arranged on an outer peripheral surface of the outer
bearing ring of the rolling bearing that is connected to the
rotating machine part and in which the stator surrounds the outer
bearing ring.
8. The direct drive according to claim 7, wherein the stator ring
segments and the stop elements of the stator as well as the
scanning sensor and the angular pitch graduation of the measuring
system including the magnets are sealed from environmental
influence by an annular housing made of stainless steel pot-shaped
sheets.
Description
FIELD OF THE INVENTION
[0001] The invention concerns a direct drive for a rotation
machine, the direct drive being advantageously suitable for use
with container treatment machines.
BACKGROUND
[0002] Container treatment machines are used above all in the
beverages and medicine industry as also in the chemical industry
and are known in the most different of forms as stretching-blowing
machines for the manufacture of plastic containers or as machines
for cleaning, filling, sealing, printing and labelling bottles,
cans, tubes or other containers made out of a plastics or metallic
material. They are made as a general rule as rotary machines
consisting substantially of a fixed machine part and a machine part
rotating about a vertical machine axis, the rotating machine part
being rotationally connected to the fixed machine part by means of
a roller bearing arranged between the two machine parts and
consisting of an outer bearing ring, an inner bearing ring and a
plurality of rolling elements rolling between said bearing rings.
On the rotating machine part are generally arranged a turntable and
a plurality of treating stations comprising functional elements
that are adapted to the respective type of treatment and interact
with the containers to be treated. Depending on the size and the
purpose of use of the plant, these turntables can have a diameter
of up to 7 m and a weight of up to 7 tons and are operated at
rotational speeds of up to 6 min.sup.-1 and, despite the resulting
high load, their rotational speed must be precisely controllable in
order to enable, for example, a compensation for fluctuations of
capacity.
[0003] According to WO 2008/022737 A1, such container treatment
machines are driven conventionally through a servomotor that uses
an appropriate step-down gear unit to move a pinion that engages a
gearing on the rotating machine part and thus makes it turn.
[0004] A drawback of such a conventional drive, however, is that
this drive does not operate without wear and the pinion-and-gearing
combination must be intensively greased regularly in order to
assure the desired durability. However, as a result, it is possible
for the surroundings to be contaminated by dripping lubrication
grease which, with a view to the applicable hygienic regulations,
is a drawback particularly in beverage bottling plants. In
addition, due to the pinion-and-gearing combination, acoustic noise
and body-borne sound as also mechanical dissipation of energy are
generated during rolling, and this contributes to an undesired high
noise level and is detrimental to the energy efficiency of the
plant. Moreover, it has been noted in conventional drive concepts
that in the case of an emergency shut-down, the machines driven by
these drives cannot be decelerated by the motors in case of an
emergency shut-down due to the high moment of inertia of the
rotationally mounted machine part because this would overload and
destroy the gear unit and the pinion. This therefore necessitates
the use of additional mechanical brakes thus disadvantageously
increasing work and costs required by the machine.
[0005] To avoid these drawbacks WO 2008/022737 A1 therefore
proposes to make the drive of a container treatment machine as a
direct drive using a torque motor, wherein in place of the hitherto
used gearing, a continuous crown with a plurality of magnets is
provided on the rotating machine part and, on the fixed machine
part is arranged at least one stator made up of a plurality of
electric coils that covers only a fractional sector of the magnet
crown, so that through an electromagnetic field generated by
energising the stator, in interaction with the magnets, the
rotating machine part can be set into a defined rotational motion.
The size of the stator and the number of integrated electric coils
are variable and depend on the size, the needed torque and the
required rotational speed of the turntable. For achieving a maximum
torque, it is recommended to arrange a plurality of such stators
around the crown of magnets.
[0006] Such a direct drive no doubt has the advantage that it no
longer comprises a mechanical connection between the fixed and the
rotating part and therefore operates free of wear. It has however
proved to be disadvantageous because the individual stators cover
the magnets only partly, so that many angular regions between the
segment-shaped stators are freely accessible and constitute a
potential source of danger for the assemblers and operators because
of the high forces of attraction of the magnets arranged
unprotected on the rotating machine part. It is likewise a drawback
that, for supporting the magnetic forces of attraction acting in
radial direction between the stators and the magnets, the
individual segment-shaped stators are fixed on the fixed machine
part by fastening screws that are screwed into the stators because
as a result of this the fixed machine part and the bearing ring of
the rolling bearing connected to this can get deformed due to the
load being applied only segment-wise so that the functioning and
the durability of the rolling bearing is limited. Over and above,
it is a further drawback that, in particular, in the case of very
large turntable diameters that are operated with very high torques,
the magnets generally fixed on correspondingly large rolling
bearings between the fixed and the rotating machine part are
required in very large piece numbers and, due to the exposed
angular regions between the individual stators, also in very large
dimensions so that, because of their very high world market price,
they cause very high manufacturing costs for the drive.
SUMMARY
[0007] Departing from the described drawbacks of the prior art, the
invention is based on the object of providing a concept for a
direct drive for a rotation machine, in particular for a container
treatment machine, which effectively avoids the drawbacks that
result from the exposed angular regions between the individual
stators and their fixing on the fixed machine part.
[0008] The above object is achieved by the invention in a direct
drive by the fact that the stator on the fixed machine part is made
as a full ring, without any gap, configured continuously over
360.degree. and covering all the magnets on the rotating machine
part while being made up of a plurality of adjoining stator ring
segments that are connected to one another through an electrical
series connection, and of a plurality of stop elements disposed
between the stator ring segments for fixing the stator ring
segments in circumferential and in radial direction.
[0009] Advantageous embodiments and further developments of the
direct drive configured according to the invention will be
described in the dependent claims.
[0010] Thus, in the direct drive configured according to the
invention, each of the individual stator ring segments is made up
of a ferrous metal yoke and of a plurality of toothed metal sheets
stacked on one another on an upper and a lower side of the yoke
with copper coils wound around the teeth of the sheets for forming
individual electric coils. The number of teeth and of the electric
coils formed by them is variable and depends on the size and number
of the individual stator ring segments, the magnitude of the
required torque and of the required speed of rotation of the
turntable as well as on the number and size of the magnets used. It
is proved to be particularly advantageous to make all the magnets
as permanent magnets out of the materials hard ferrite,
samarium-cobalt or neodymium-iron-boron and to fix them on the
outer peripheral surface of the outer bearing ring of the rolling
bearing connected to the rotating machine part.
[0011] A further characterising feature of the direct drive
configured according to the invention is that the individual coils
of the stator ring segments are connected electrically in series
through a star-delta connection with three electrically offset
phases of 120.degree. and are controllable through a single servo
controller with a voltage intermediate-circuit converter. In this
way, each coil of the stator is successively activated,
phase-displaced relative to the preceding coil, so that the
circulating electromagnetic fields generated cause, in interaction
with the magnetic fields of the permanent magnets, a rotary motion
of the rotating machine part. All the adjoining stator ring
segments are connected through a respective connecting cable to one
another through a plug connector and only one first and one last
stator ring segment comprises, in place of a connecting cable, a
servo controller connection or a star-delta element. Besides this,
it is advantageous if the voltage intermediate-circuit converter
permits a bidirectional flow of power because, in this way, an
emergency operation program can be provided in the controls which,
in the case of a machine standstill or a line failure, permits a
synchronised angular switch-off of the coils of all the stator ring
segments and of all other drives of a complex plant using the power
return flow into the power network.
[0012] A further feature of the direct drive configured according
to the invention is that the stop elements arranged between the
stator ring segments preferably have the shape of circular ring
segments that are in abutting contact with the yoke having a
lengthened shape and with the radial side surfaces of the stator
ring segments. These stop elements in form of circular ring
segments are screwed onto the fixed machine part preferably in such
a way that their inner side pointing in direction of the magnets is
arranged as an extension of the inner sides of the stator ring
segments. The yokes of the stator ring segments, the outer side of
which at the same time forms the outer side of the stator ring
segments, are configured longer than the stator ring segments on
both sides and bear with the inner sides of their extensions
against the outer sides of the stop elements. The radial side
surfaces of the stator ring segments that are disposed at shorter
distances to one another, in contrast, bear against the side
surfaces of the stop elements, so that the angular position of the
stator ring segments relative to one another and their interferric
gap with the magnets are defined and assured. However, it is also
possible to fix, in place of circular ring-shaped stop elements,
appropriate stop pins or the like on the fixed machine part,
against which pins the lengthened yokes and the radial side
surfaces of the stator ring segments bear in the same way.
[0013] Moreover, a further advantageous development of the direct
drive configured according to the invention is that one of the stop
elements is conceived at the same time as a holder for a scanning
sensor that, with an incremental or absolute, magnetic or inductive
angular pitch graduation, forms on the rotating machine part, a
measuring system for determining of the position of the rotating
machine part. It has proved to be particularly advantageous to fix
the scanning sensor directly on one of the stop elements and to
arrange the angular pitch graduation on the outer peripheral
surface of the rotating outer bearing ring of the rolling bearing
which is arranged between the machine parts. In this way, it is
possible to detect the respective angular position of the turntable
of the rotation machine on the outer bearing ring itself, i.e.
directly and in a torsion-proof manner and thus without errors and
to permanently regulate the position of the turntable through
interaction with a position control system implemented in the servo
controller. Alternatively, however, it is also possible to fix the
scanning sensor on the end face of the fixed inner bearing ring and
to arrange the angular pitch graduation on the inner peripheral
surface of the rotating outer bearing ring.
[0014] A preferred form of embodiment of the direct drive
configured according to the invention is to configure the direct
drive as an inner-rotor motor in which the magnets of the torque
motor and the angular pitch graduation of the measuring system are
preferably arranged on the outer peripheral surface of the outer
bearing ring of the rolling bearing that is connected to the
rotating machine part, and in which the stator surrounds the outer
bearing ring. In an alternative form of embodiment of the direct
drive configured according to the invention, however, it is
possible to make the direct drive as an outer-rotor motor in which
the magnets of the torque motor and the angular pitch graduation of
the measuring system is arranged on the inner peripheral surface of
the inner bearing ring of the rolling bearing that is connected to
the rotating machine part, and in which the stator surrounds the
inner bearing ring.
[0015] Finally, it is proposed as an advantageous further
development of the direct drive configured according to the
invention to seal the stator ring segments and the stop elements of
the stator as well as the scanning sensor and the angular pitch
graduation of the measuring system including the magnets from
environmental influence through an annular housing out of stainless
steel pot-shaped sheets. This has proved to be particularly
advantageous in the case of beverage bottling plants because this
prevents the penetration of liquids into the drive and thus reduces
the expenses for maintaining the cleanness of the beverage bottling
plant.
[0016] The direct drive for a rotation machine configured according
to the invention thus has the advantage over the direct drives
known from the prior art that the stator of the torque motor is
configured as a complete full ring of 360.degree. that always
covers all the magnets on the rotating machine part independently
of the diameter, the torque and the circumferential speed of the
turntable of the rotation machine and thus no longer comprises any
exposed angular regions between individual stators and the magnets
that could be a potential source of danger for the assemblers and
the operators. At the same time, the complete full ring is
available for torque transmission to the turntable, so that a
reduction of the track height and the track width of the permanent
magnets and therefore makes it possible to save high-cost magnetic
material. The build-up of the stator out of individual,
series-connected stator ring segments with intermediately disposed
stop elements that therefore cannot be separately operated has the
advantage that the time and costs for the laying of cables of all
the stator ring segments is substantially lower than that for
separately connected stators and that, in case of repair and
maintenance, individual stator ring segments can be replaced in
radial direction without the need of disassembling or lifting the
heavy turntable of the rotation machine. It is true, of course,
that if in such a case of repair of maintenance, one of the stator
ring segments is removed, the entire stator is not operable due to
the interrupted flow of current through all of the stator ring
segments, but this is not a drawback because, in the case of
maintenance or repair, all the drives are de-energised. Moreover,
by reason of the stator ring segments and the stop elements
arranged between these, the radially inwardly acting magnetic
forces of attraction between the stator ring segments and the
permanent magnets are supported within the thus formed stator ring,
so that the fixed machine part and the bearing ring of the rolling
bearing connected to this can no longer get deformed.
[0017] In addition, the reliability of the direct drive of the
invention on container treatment machines can be furthered enhanced
if the rolling bearing arranged between the fixed and the rotating
machine part is equipped with a lubricant quality sensor known from
DE 10 2007 042 254 A1. This can be fixed in such a way in a radial
bore in the fixed bearing ring, which bore extends to within the
rolling element raceway that, through its sensitive front end, the
water content, the ageing, the temperature and the degree of
impurity of the lubricant in the rolling element raceway can be
continuously measured during the operation of the plant. As soon as
one of these measured values exceeds the respective pre-set
threshold value, a warning signal is transmitted via a strobing
electronic unit to the machine controls, so that a re-lubrication
through a grease pump arranged in a further radial bore inside the
bearing ring, or maintenance work can be implemented. In
particular, in the case of beverage bottling plants it has proved
to be particularly advantageous to monitor the level of humidity of
the lubricant in the rolling bearing of the turntable because
beverage bottling plants are treated regularly with aqueous
cleansing agents and disinfectants. With the help of the lubricant
quality sensor it is then possible to implement re-lubrication
through the grease pump only if this is really required, so that,
in this way, the input of lubricant into the rolling bearing is
optimised and the maintenance of the cleanness of the entire
machine is improved.
[0018] A further enhancement of the reliability and availability of
the direct drive of the invention on container treatment machines
is possible, in addition, if a state monitoring system, known per
se, is likewise integrated into the rolling bearing between
arranged between the fixed and the rotating machine part. Such a
state monitoring system consists substantially of an acceleration
sensor with a downstream amplifier and evaluation system, with the
help of which vibrations or solid-borne sound, which occur when
rolling elements roll over damaged raceways on one or both of the
bearing rings, can be detected and evaluated. The acceleration
sensor is screwed in such a way into a further radial bore in the
inner peripheral surface of the fixed bearing ring that it is
arranged very close to and opposite the rolling element raceway and
the rolling elements.
[0019] Finally, a further advantage of the direct drive configured
according to the invention over the direct drives known from the
prior art with a plurality of separate sensors in which individual
temperature sensors are used to measure the coil temperature of
each stator and which, in the case of the pre-set temperature
switching point being exceeded, have to be de-energised through the
servo controller, consists in that only one single stator ring
segment has to be equipped with a temperature sensor for monitoring
the coil temperature and be connected to the servo controller,
because all the stator ring segments together form a functional
torque motor only in interaction with one another and only when
arranged to form a full stator ring.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] A preferred form of embodiment of the direct drive
configured according to the invention will be described more
closely in the following with reference to the attached drawings.
The figures show:
[0021] FIG. 1, a schematic representation of a top view of a direct
drive configured according to the invention, for a container
treatment machine;
[0022] FIG. 2, the enlargement of a cross-section through the
direct drive of the invention, with a fixed machine part and a
rotating machine part;
[0023] FIG. 3, the schematic representation of the electrical
connection scheme of the direct drive configured according to the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] The sectional representation shown in FIG. 2 discloses a
direct drive suitable for a container treatment machine. The direct
drive is made up substantially of a fixed machine part 1 and a
machine part 2 rotating about a vertical axis of the machine; the
rotating machine part 2 is rotatably connected to the fixed machine
part 1 through a rolling bearing 3 which is arranged between the
machine parts 1, 2 and comprises an outer bearing ring 4, an inner
bearing ring 5 and a plurality of rolling elements 6 that roll
between said bearing rings 4, 5, which rotating machine part can be
driven by a torque motor 7. In a combined view with FIGS. 1 and 3
it becomes clear that a plurality of magnets 8 is arranged
circumferentially on the rotating machine part 1 and that a stator
12 made up of a plurality of electric coils 9, 10, 11 is arranged
on the fixed machine part 1 so that, through an electromagnetic
field generated upon energising of the stator 12, in interaction
with the magnets 8, the rotating machine part 2 can be put into a
defined rotational movement.
[0025] In addition, it can be seen in FIG. 1 that, as proposed by
the invention, the stator 12 on the fixed machine part 1 is
configured as a full ring of 360.degree. that covers all the
magnets 8 on the rotating machine part 2, without a gap, and is
made up of a plurality of stator ring segments 13.1, 13.2, 13.3,
13.4, 13.5 arranged adjoining one another and connected to one
another through an electrical series connection, and of a plurality
of stop elements 14.1, 14.2, 14.3, 14.4, 14.5 that are arranged
between the stator ring segments 13.1, 13.2, 13.3, 13.4, 13.5 and
serve to fix the stator ring segments 13.1, 13.2, 13.3, 13.4, 13.5
in peripheral and in radial direction. In an exemplary embodiment,
the magnets 8 of the torque motor 7 are arranged on the outer
peripheral surface of the outer bearing ring 4 of the rolling
bearing 3 that is connected to the rotating machine part 1, while
the stator 12 surrounds the outer bearing ring 4 completely.
[0026] As can be seen further in FIGS. 1 and 2, the individual
stator ring segments 13.1, 13.2, 13.3, 13.4, 13.5 of the stator 12
are made respectively of a ferrous metal yoke 15 and of a plurality
of toothed metal sheets 16, stacked on one another on the upper and
lower side of the yoke 15, and copper coils are wound around the
teeth of the metal sheets to form the individual electric coils 9,
10, 11. As illustrated in FIG. 3, these individual coils 9, 10, 11
are connected through a star-delta connection electrically in
series in three electrical phases offset to one another by
120.degree. and can be activated through a single servo controller,
not shown, with a voltage intermediate-circuit converter 17. All
the adjoining stator ring segments 13.1, 13.2, 13.3, 13.4, 13.5 are
connected to one another through a respective connecting cable 18
with a plug connector 19, and only one first and one last stator
ring segment 13.1, 13.5 comprises, in place of a connecting cable
18, a servo controller connection 20 and a star-delta element 21
respectively.
[0027] FIG. 1 likewise shows that the stop elements 14.1, 14.2,
14.3, 14.4, 14.5 arranged between the stator ring segments 13.1,
13.2, 13.3, 13.4, 13.5 have the shape of circular ring segments
that are in abutting contact with the lengthened yokes 15 and with
the radial side surfaces, not specifically referenced, of the
stator ring segments 13.1, 13.2, 13.3, 13.4, 13.5. In addition, the
stop element 14.2 arranged between the stator ring segments 13.1
and 13.2 also serves as a holder for a scanning sensor 22 that
forms, together with an incremental or absolute, magnetic or
inductive angular pitch graduation 23 arranged, as shown in FIG. 2,
likewise on the outer peripheral surface of the outer bearing ring
4 of the rolling bearing 3 connected to the rotating machine part
1, a measuring system for determining the position of the rotating
machine part 1.
[0028] Finally, it can be seen in FIG. 2 that the stator ring
segments 13.1, 13.2, 13.3, 13.4, 13.5 and the stop elements 14.1,
14.2, 14.3, 14.4, 14.5 of the stator 12 as also the scanning sensor
22 and the angular pitch graduation 23 of the measuring system
including the magnets 8 are sealed from environment influence by an
annular housing 24 made of stainless steel pot-shaped sheets. This
has proved to be particularly advantageous, in particular in the
case of direct drives for beverage bottling plants because, in this
way, the penetration of liquids into the direct drive is
avoided.
TABLE-US-00001 List of reference numbers 1 Fixed machine part 2
Rotating machine part 3 Rolling bearing 4 Outer bearing ring of 3 5
Inner bearing ring of 3 6 Rolling element of 3 7 Torque motor 8
Magnets 9 Coils 10 Coils 11 Coils 12 Stator 13.1 Stator ring
segment 13.2 Stator ring segment 13.3 Stator ring segment 13.4
Stator ring segment 13.5 Stator ring segment 14.1 Stop element 14.2
Stop element 14.3 Stop element 14.4 Stop element 14.5 Stop element
15 Yokes of 9, 10, 11 16 Toothed sheets of 9, 10, 11 17 Voltage
intermediate-circuit converter 18 Connecting cable 19 Plug
connector 20 Servo controller connection 21 Star-delta element 22
Scanning sensor 23 Angular pitch graduation 24 Housing
* * * * *